Slide-valve.



No. 64!,l32. Patented Ian. 9, I900.

I. N. MOORE.

SLIDE VALVE.

(Applicatiun filed Apr. 6, 1899.) I

(No Model.)

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ILA N. MOORE, OF BATTLE CREEK, MICHIGAN.

8 LI DE-VALVE.

SPECIFICATION forming part of Letters Patent No. 641,132, dated January9, 1900. Application filed April 6, 1899. Serial No. 711,981- (Nomodel.)

To all whom it may concern:

Be it known that I, ILA N. MOORE, of Battle Creek, in the county ofCalhoun and State of Michigan, have invented a new and ImprovedSlide-Valve, of which the following is a full, clear, and exactdescription.

The invention relates to slide-valves for steam-engines, steam-pumps,and. motors; and its object is to provide a new and improved slide-valvewhich is simple and durable in construction and arranged to admit auniform amount of steam to the cylinder, irrespective of a short or longstroke of the slide-valve, to insure uniform work of the engine.

The invention consists of novel features and parts and combinations ofthe same, as

' will be fully described hereinafter and then pointed out in theclaims.

A practical embodiment of my invention is represented in theaccompanying drawings, forming a part of this specification, in whichsimilar characters of reference indicate corresponding parts in both theviews.

Figure l is a longitudinal sectional side elevation of the improvement,and Fig. 2 is a plan view of theValVe.

In steam-pumps as heretofore constructed it is frequently observed thatwhen the pump does heavy work the piston travel and that of the valveare shorter than when the pump is doing light work. For instance, if thepump is used for supplying the boiler with the feed-water and thedischarge of the pump is changed from the boiler, say, to an open tankthen the pump with the same set of throttle will immediately change to alonger stroke, both with the piston and the admission, than the one ithad during the time the feed-water was pumped into the boiler againstboiler-pressure. Thus, owing to the shorter travel of the valve, lesssteam is admitted under a heavy load-that is, at the very time when moresteam should be admitted-and when the load is reduced the strokeincreases, and the valve consequently admits more steam, causing thepiston steam to hammer and pound unless the throttle is reset by theengineer to admit less steam. In order to overcome this difficulty andassure of admitting a uniform amount of steam to the cylinder under thevarious conditions of the valve, es=

pccially when the pump is doing variable work, I provide theimprovements presently to be described in detail.

As shown in Fig. 1, theimprovement is applied to a steam pump having theusual steamcylinder A, in which reciprocates a piston 13, connected by apiston-rod G with the plunger in the pump cylinder. (Not shown.) Thesteam-cylinder A is provided with the usual admission-ports a and. b andthe exhaust-port c, and the said ports are controlled by a slide-valveD, held to move in a steam-chest E, connected with a suitable source ofsteamsupply. The slide-valve D is controlled by The usual piston F,fitted to slide in the steam-chest E and shifted automatically from oneside to the other by steam admitted to the ends of the piston throughports controlled by an auxiliary slide-valve G, having its stem IIoperated by a rockerarm I, actuated from the piston-rod O. Theconstruction of the valve Gand the piston F, carrying the slide valve D,is of the ordinary kind, so that further description of the same is notdeemed necessary.

The wings D D of the slide-valve D are made sufficiently long to keepthe admissionports a and bi covered when the slide-valve is at the endsof its stroke, and in said wings are arranged ports e and f, adapted toregister with the admission-ports a and 5, respectively, said ports 6and f being located on the wings at such points that they register withthe corresponding ports a and 5 during both a long and short stroke-ofthe valve D, so that a uniform amount of steam is admitted to thecylinder A during either a long or a short stroke of the slide-valve D.As shown, the ports e on one wing are larger than those f on the otherwing, (or to secure the same function the ports might be alike in size,but different in number.) The passage area is thus different for onewing from the other. This construction is of advantage when, as often isthe case, the piston B has work to do only going one way, the largerpassage area of one wing of the slide-valve supplying the requiredlarger quantity of steam for the working stroke, while the passage ofthe other wing, being of reduced area, admits only steam enough toreturn the piston B during the inactive stroke.

As shown in Fig. 1, the portsfare in register with the admission-portsI), while the port a is connected by the slide-valve d with theexhaust-port c, and steam can pass from the steam-chest E by way of theregistering portsfandb to the inner end of the cylinder A to move thepiston 13 to the left to finally reach the position shown in saidFig. 1. During the travel of the piston B to this position thepiston-rod O actuat-es the rocker-arm I and shifts the stem H and thevalve Gto the position shown in dotted lines, so that the valve Guncovers the port leading from the steam-chest E to the left-hand end ofthe piston F, and-the latter is now shifted to the right to carry theslide-valve D in the same directionthat is, to move the ports f out ofregister with the port I) and to move the ports 6 in register with theport a. Steam now passes from the steam-chest E to the left-hand end ofthe cylinder A to move the piston 13 to the right on the return stroke.from the foregoing that in either case the ports a andf register withthe ports (t and b, which are considerably wider than the diameters ofthe ports e and f, and consequently a uniform amount of steam isadmitted to the ends of the cylinder irrespective of the long or shortstroke of the valve D.

It is well known that in ordinary slidevalves the wings are short enoughto open the ports a and Z) full width when making a full-length strokeand only open a small portion of said ports when .doing heavy duty onthe short stroke.

Although the improvement is shown as applied to a valve moved by apiston, it is evi- It is evident dent that other means for shifting thevalve may be used-for in'stance,the valve-stem and outside connectionstogive the ordinary sliding motion to the valve.

It is understood that in actual practice the speed of a steam-pump isretarded when doing heavy work, (boiler-feeding) and when with myimprovement the desired speed is given to the pump by selecting thenumber and size of the ports 6 andfaccordingly it is evident that thevalve will fully answer the purpose when the pump is doing light workthat is, filling a tank.

Having thus fully described my invention, I claim as new and desire tosecure by Letters Patent 1. The combination with the cylinder havingsuitable ports, of a slide-valve having through-ports of less diameterthan the cylinder-ports and adapted to register therewith, the ports atone end of the valve being of a different area from those at the otherend, and means for operating the valve.

2. A slide-valve, provided with extended wings for covering, at alltimes, the admission-ports to the cylinder, said wings being providedwith ports adapted to register with the admission-ports on either ashort or a long stroke of the valve, the ports on one of the wings beingof a different area from those on the other wing, substantially as shownand described.

ILA N. MOORE.

Witnesses:

N. Y. GREEN, J. W. WILKINS.

